2
def get_input():

    '''
    Continually prompt the user for a number, 1,2 or 3 until
    the user provides a good input. You will need a type conversion.
    :return: The users chosen number as an integer
    '''
    #pass # REPLACE THIS WITH YOUR CODE

    n = input ("Enter the number 1,2 and 3? ")

    while n > 0 and n < 4:
        print("Invalid Input, give the  number between 1 to 3")
        n = input ("Enter the number 1,2 or 3? ")
    return (n)


get_input()

I am not getting the answer and it's just not working, I am looking for answer like this, 

Give me one of 1,2 or 3: sid
Invalid input!
Give me one of 1,2 or 3: 34
Invalid input!
Give me one of 1,2 or 3: -7
Invalid input!
Give me one of 1,2 or 3: 0
Invalid input!
Give me one of 1,2 or 3: 2

Process finished with exit code 0
Nayuki
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Arslan Ahmed
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  • Your code would have spit out an error `TypeError: unorderable types...`, when you ask a question include the error and the traceback, *it's just not working* is usually not very informative, even if you cast your code will crash if a user enters a string that cannot be cast to an int, you should use a try/except – Padraic Cunningham Oct 04 '15 at 16:53

1 Answers1

3

The input() built-in function returns a value of type str.

As is specified in the (doc)string right after the declaration of function get_input():

You will need a type conversion.

So, you must wrap it in an int() to convert it to an integer int.

n = int(input("Enter the number 1,2 or 3? "))

Then you can use comparison operators to evaluate if it is in the qualified range of accepted values :

   # Your comparisons are mixed.
   # You can use the in operator which is intuitive and expressive
   while n not in [1, 2, 3]:
        print("Invalid Input, give the  number between 1 to 3")

        # remember to wrap it in an int() call again
        n = int(input ("Enter the number 1,2 or 3? "))
    return (n)

If you supply numbers this works perfectly:

Enter the number 1,2 and 3? 10
Invalid Input, give the  number between 1 to 3
Enter the number 1,2 and 3? -1
Invalid Input, give the  number between 1 to 3
Enter the number 1,2 and 3? 15
Invalid Input, give the  number between 1 to 3
Enter the number 1,2 and 3? 104
Invalid Input, give the  number between 1 to 3

But if you supply a single character or a string (type str), you'll get an error: 

Enter the number 1,2 and 3? a

ValueError: invalid literal for int() with base 10: 'a'

This is beyond the scope of the question but you might want to look into it.

Anyway, your while condition is setting me off..

It seems that you might be using Python 2 with the print_function imported through __future__. (or else the comparison between different types would raise a TypeError in the while statement).

Check your version of python python -V [in the command line] and:

If using python 2 instead of input() use raw_input():

n = int(raw_input("Enter the number 1, 2, 3: ")

If I am wrong and you are indeed using Python 3.x, use int(input()) as explained.

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Dimitris Fasarakis Hilliard
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